Newly developed radar antennas must be tested to determine their performance. This is most often done in a laboratory environment where the antenna may be connected to sophisticated electronic measurement instrumentation. Since a line of sight between the radar antenna and target must be present, an unsightly and costly temporary fiberglass radome-like structure must be constructed on the exterior of a laboratory building. Another alternative is to install roll-up steel doors. As will be appreciated, this is an aesthetically unacceptable choice where the architectural appearance of the laboratory building is of importance.